Self contracting stent

Abstract

A self-contracting stent for use at a treatment site comprising shape memory material is provided. The stent may have an initial diameter for delivery to the treatment site and an expanded diameter when deployed at the treatment site. The stent further may have a contracted diameter when subjected to a temperature at or above a transition temperature. The contracted diameter is less than the expanded diameter and permits repositioning or removal of the stent from the treatment site. Additionally, a method for delivering and recovering the stent from a treatment site is provided. The method includes delivering a stent to a treatment site and expanding the stent at the treatment site so that the stent is deployed at the treatment site. The method further includes changing the temperature of the stent at the treatment site to at least a transition temperature to cause the stent to contract.

Description

RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 651,028, filed Feb. 8, 2005.BACKGROUND OF THE INVENTION [0002] The present invention relates to a stent used to ensure a desired inner diameter of a tubular organ or bodily lumen, and in particular, to a method for delivering and recovering the stent. [0003] Stents are often employed to maintain the internal diameter of a bodily lumen, and in particular, to maintain the expanded internal diameter of a bodily lumen that has been expanded by a related medical procedure. For example, in an angioplasty procedure, a narrowed portion of the coronary arteries may be expanded with an angioplasty catheter. It is then typically necessary to take measures to prevent the expanded portion from being narrowed again. In such a case, an expansion retainer, hereinafter referred to as “stent,” is generally used for ensuring a desired inner diameter of a bodily lumen. For ensuring expansion of, for e...

AI Technical Summary

Benefits of technology

[0007] Therefore, a need exists for an expandable stent that can be efficiently and safely removed aft

Problems solved by technology

Thus, it may be quite difficult to remove a stent left in the blood vessel, even after recovery of the body part to which the surgical operation was applied.

In addition, it can be very difficult to change the position of the stent once it has been deployed and expanded.

This may be problematic if the stent has been placed in an erroneous position or location during the initial deployment.

However, plastic stents have two disadvantages.

First, plastic stents are typically not expandable.

Second, the diameter of a plastic stent is limited by the delivery system, typically a catheter, especially if delivered through an endoscope (˜11.5 French maximum).

Due to the limited diameter of endoscopically delivered plastic stents, these stents are often prone to clogging (e.g., stents deployed in the bile or pancreatic duct) and may have to be replaced every three months, or even more frequently.

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